Abstract Substantial evidence supports the efficacy of psychosocial interventions for individuals with severe mental illness and considerable human and financial resources have been spent developing, testing, and training frontline providers in such evidence-based practices (EBPs). Yet, the delivery of what works to service users has been stymied within real world mental health service settings. Failure to translate these efficacious interventions to community settings has resulted in limited access to quality care, service disengagement, and poor treatment outcomes. During translation efforts, individual providers make decisions about whether to adopt a new practice into their work. Poor attitudes towards EBPs, perceptions of limited efficacy, and lack of availability of resources to support new learning have negatively influenced providers' adoption of new interventions. Strategies are urgently needed to overcome these barriers and realize US policy mandates for equitable access to evidence-based, recovery-oriented, theoretically-driven community mental health services. Supervisors in community mental health settings provide both clinical practice and administrative oversight of frontline provider practice. Given their proximal and often daily interactions with providers, supervisors are uniquely positioned to be EBP champions and overcome on-the-ground implementation challenges. In controlled EBP efficacy trials, supervision has been found to improve implementation outcomes. In real world settings, however, supervision can vary ? leading to limited opportunities for providers to learn EBPs, inadequate organizational social context for implementation, and poor service user outcomes. This proposed fellowship application seeks to gain insight into this key nexus between frontline providers and their direct supervisors and how their interaction drives adoption of new practices in the context of a large scale, NIMH- funded Person-Centered Care Planning and Service Engagement (PCCP) trial. Embedded within the PCCP project, phase #1 of this F31 will include a quantitative examination of the associations between supervisory leadership at baseline and supervisees' self-assessments of their adoption of PCCP at 12-month follow-up, with specific attention to the alignment between supervisors' and supervisees' ratings of supervisory leadership. In order to further interpret Phase #1 findings and to identify mechanisms of supervisory influence, Phase #2 will involve a qualitative examination of provider perspectives regarding the role of supervisors in their adoption of PCCP, using a grounded theory approach with multiple data sources (interviews and observation). The primary goal is to examine supervision as an implementation strategy to translate EBPs into service delivery. This proposed grant will contribute to the NIMH priority to improve the efficiency and effectiveness of existing community mental health services by generating new knowledge of how supervision, a mechanism already embedded in routine clinical care, can be maximized to improve dissemination of EBP.